Vehicular power take-off (PTO) systems are known which provide for a mechanical output from an internal combustion engine or portion of the vehicle drivetrain to drive accessory loads such as electrical generators or mechanical or hydraulic apparatus including hydraulic pumps for providing a source of pressurized working fluid to hydraulically powered apparatus. PTO is operator invoked generally in accordance with one or more selected engine speed settings. PTO engine speed settings may also be incremented or decremented or changed at predetermined rates to a new set speed. Speed control of the engine ultimately depends upon the engine torque required to provide the needed PTO torque requirements at the selected set speed. Torque is generally a function of intake air ingested by the internal combustion engine and intake air is controlled by throttling.
PTO is typically enabled and speed settings selected at an operator interface, such as a control console located within a passenger compartment or remote therefrom, such as in a basket of a personnel extension boom, having conventional switch, button or lever inputs to enable the PTO system and indicate the operator intentions. Redundant sets of control switches are not uncommon. The various operator interface inputs are conveyed to an engine controller for effecting set speeds through throttle controls responsive to such inputs. Engine controls have conventionally acted directly upon the inputs to effect throttle changes in accordance with the inputs.